The United States should send military personnel into Syria to train and equip opposition forces and to help prevent the civil war there from destabilizing the region, House Intelligence Chairman Mike Rogers said Sunday.

The Michigan Republican said on CBS’ “Face the Nation” that there is “mounting evidence that it is probable” the regime of Syrian President Bashar al-Assad has used “at least a small quantity” of chemical weapons against opposition forces during the past two years.

The Obama administration has said repeatedly that the use of chemical weapons or preparation for their use would warrant greater U.S. involvement in the conflict. But the administration said there is no conclusive evidence that such weapons have been used by either side.

“I think it is abundantly clear that that red line has been crossed,” Rogers said.

President Barack Obama’s posture toward military involvement in Syria has been indecisive, Rogers said, frustrating U.S. allies and posing a danger to U.S. interests. The president noted during a trip to the Middle East last week that the situation in Syria poses something of a problem for U.S. policy and that he would likely be criticized no matter what course he takes.

Rogers called for the use of small numbers of U.S. troops with special capabilities to help make opposition forces in Syria more effective. “This doesn’t mean the 101st Airborne Division and ships,” he said. “We can do this in a way that doesn’t lure the United States into a big-boots, on-the-ground conflict.”

Should Assad’s rule collapse in the current environment, Rogers warned, there would be “mass chaos” involving elements of al-Qaida, Hezbollah and Hamas trying to gain control of the government’s arsenal, including chemical weapons.

Senate Armed Services Chairman Carl Levin, D-Mich., and Arizona Republican Sen. John McCain urged Obama last week to begin “limited military operations” to force Assad out of power. Levin and McCain outlined several options that they said would not require the United States to put troops on the ground in Syria or act unilaterally. But they stressed that it was in the United States’ national security interest to take “more active steps,” along with allies in the Middle East and Europe, to stop the violence in Syria.